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Title: Federal Reference Method for Lead in Total Suspended Particulate Matter

Abstract: On November 12, 2008 EPA substantially strengthened the national ambient air quality standards (NAAQS) for lead. EPA revised the level of the primary (health-based) standard from 1.5 micrograms per cubic meter (g/m3) to 0.15g/m3, measured as total suspended particles (TSP) and revised the secondary (welfare-based) standard to be identical in all respects to the primary standard. In conjunction with strengthening the lead (Pb) NAAQS, EPA identified the need for states to improve existing lead monitoring networks. Depending on specific circumstances, States may have the option of using monitoring for either lead in TSP (Pb-TSP) or lead in PM10 (Pb-PM10) using approved Federal Reference Methods (FRMs) or Federal Equivalent Methods (FEMs) to meet monitoring requirements. To support new monitoring requirements, an FRM for Pb-PM10 was developed with the November 8, 2008 rulemaking. The FRM for Pb-TSP was left unchanged. The Pb-TSP FRM was promulgated in 1978. EPA recognizes that significant advances in measurement technology have been made since the promulgation of the original FRM. In order to support new monitoring requirements for Pb-TSP and update the FRM to improve it based on advanced measurement technology, a new FRM must be developed.